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Near-thermal lSF atoms, produced by the 19F(n,2n)18F nuclear reaction and moderated in kinetic energy by collisions with excess SFs, have been reacted with the fluorinated ethylenes. The radicals formed by '8F addition are predominantly collisionally stabilized at 5 atm of pressure and are identified after abstraction of H from HI as the corresponding fluoroalkane-l*F. In intermolecular competition, the 18F atoms react preferentially with less fluorinated positions. Intramolecularly, I8F addition is also preferred at the less fluorinated end of the molecule. The competitive reaction ratios per molecule are generally independent of olefin/HI ratios, as well as of the ratios of two competing olefinic substrate molecules. The decomposition by CF, loss of CHFI8FCF2* radicals from near-thermal addition of 18F to CHF==CF2 proceeds with a pressure for half stabilization of 45 i 5 Torr in CHF=CF2.he energetic 18F atoms formed by nuclear reactions

but from a far more reactive -CH20H) was made on the basis of deuterium isotope studies.Irradiation2 of VI1 yielded VI11 and formaldehyde. By nmr integration and mass spectrometry no detectable I11 was present and the formaldehyde was free of CHDO. Thus, the alcoholic hydrogen was specifically VI11 transferred. Again, the mass spectrum of VI1 correlated perfectly, with the base peak appearing at mje 144 instead of mje 143 as in the case of IV. As further confirmation of the close parallel of these reactions with type I1 cleavage and the McLafferty rearrangement we found that compound IX was completely stable to irradiation under the same conditions, while its electron impact fragmentation gave a base peak at mje 155 (vinylquinoline). In IX a six-membered transition state for H abstraction is not possible.Studies on the excited state(s) involved in these photoreactions are currently under way.

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